includes/api/ApiQuery.php

   1 <?php
   2 /**
   3  *
   4  *
   5  * Created on Sep 7, 2006
   6  *
   7  * Copyright © 2006 Yuri Astrakhan "<Firstname><Lastname>@gmail.com"
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, write to the Free Software Foundation, Inc.,
  21  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  22  * http://www.gnu.org/copyleft/gpl.html
  23  *
  24  * @file
  25  */
  26
  27 /**
  28  * This is the main query class. It behaves similar to ApiMain: based on the
  29  * parameters given, it will create a list of titles to work on (an ApiPageSet
  30  * object), instantiate and execute various property/list/meta modules, and
  31  * assemble all resulting data into a single ApiResult object.
  32  *
  33  * In generator mode, a generator will be executed first to populate a second
  34  * ApiPageSet object, and that object will be used for all subsequent modules.
  35  *
  36  * @ingroup API
  37  */
  38 class ApiQuery extends ApiBase {
  39
  40         /**
  41          * List of Api Query prop modules
  42          * @var array
  43          */
  44         private static $QueryPropModules = array(
  45                 'categories' => 'ApiQueryCategories',
  46                 'categoryinfo' => 'ApiQueryCategoryInfo',
  47                 'contributors' => 'ApiQueryContributors',
  48                 'deletedrevisions' => 'ApiQueryDeletedRevisions',
  49                 'duplicatefiles' => 'ApiQueryDuplicateFiles',
  50                 'extlinks' => 'ApiQueryExternalLinks',
  51                 'fileusage' => 'ApiQueryBacklinksprop',
  52                 'images' => 'ApiQueryImages',
  53                 'imageinfo' => 'ApiQueryImageInfo',
  54                 'info' => 'ApiQueryInfo',
  55                 'links' => 'ApiQueryLinks',
  56                 'linkshere' => 'ApiQueryBacklinksprop',
  57                 'iwlinks' => 'ApiQueryIWLinks',
  58                 'langlinks' => 'ApiQueryLangLinks',
  59                 'pageprops' => 'ApiQueryPageProps',
  60                 'redirects' => 'ApiQueryBacklinksprop',
  61                 'revisions' => 'ApiQueryRevisions',
  62                 'stashimageinfo' => 'ApiQueryStashImageInfo',
  63                 'templates' => 'ApiQueryLinks',
  64                 'transcludedin' => 'ApiQueryBacklinksprop',
  65         );
  66
  67         /**
  68          * List of Api Query list modules
  69          * @var array
  70          */
  71         private static $QueryListModules = array(
  72                 'allcategories' => 'ApiQueryAllCategories',
  73                 'alldeletedrevisions' => 'ApiQueryAllDeletedRevisions',
  74                 'allfileusages' => 'ApiQueryAllLinks',
  75                 'allimages' => 'ApiQueryAllImages',
  76                 'alllinks' => 'ApiQueryAllLinks',
  77                 'allpages' => 'ApiQueryAllPages',
  78                 'allredirects' => 'ApiQueryAllLinks',
  79                 'allrevisions' => 'ApiQueryAllRevisions',
  80                 'alltransclusions' => 'ApiQueryAllLinks',
  81                 'allusers' => 'ApiQueryAllUsers',
  82                 'backlinks' => 'ApiQueryBacklinks',
  83                 'blocks' => 'ApiQueryBlocks',
  84                 'categorymembers' => 'ApiQueryCategoryMembers',
  85                 'deletedrevs' => 'ApiQueryDeletedrevs',
  86                 'embeddedin' => 'ApiQueryBacklinks',
  87                 'exturlusage' => 'ApiQueryExtLinksUsage',
  88                 'filearchive' => 'ApiQueryFilearchive',
  89                 'imageusage' => 'ApiQueryBacklinks',
  90                 'iwbacklinks' => 'ApiQueryIWBacklinks',
  91                 'langbacklinks' => 'ApiQueryLangBacklinks',
  92                 'logevents' => 'ApiQueryLogEvents',
  93                 'pageswithprop' => 'ApiQueryPagesWithProp',
  94                 'pagepropnames' => 'ApiQueryPagePropNames',
  95                 'prefixsearch' => 'ApiQueryPrefixSearch',
  96                 'protectedtitles' => 'ApiQueryProtectedTitles',
  97                 'querypage' => 'ApiQueryQueryPage',
  98                 'random' => 'ApiQueryRandom',
  99                 'recentchanges' => 'ApiQueryRecentChanges',
 100                 'search' => 'ApiQuerySearch',
 101                 'tags' => 'ApiQueryTags',
 102                 'usercontribs' => 'ApiQueryContributions',
 103                 'users' => 'ApiQueryUsers',
 104                 'watchlist' => 'ApiQueryWatchlist',
 105                 'watchlistraw' => 'ApiQueryWatchlistRaw',
 106         );
 107
 108         /**
 109          * List of Api Query meta modules
 110          * @var array
 111          */
 112         private static $QueryMetaModules = array(
 113                 'allmessages' => 'ApiQueryAllMessages',
 114                 'siteinfo' => 'ApiQuerySiteinfo',
 115                 'userinfo' => 'ApiQueryUserInfo',
 116                 'filerepoinfo' => 'ApiQueryFileRepoInfo',
 117                 'tokens' => 'ApiQueryTokens',
 118         );
 119
 120         /**
 121          * @var ApiPageSet
 122          */
 123         private $mPageSet;
 124
 125         private $mParams;
 126         private $mNamedDB = array();
 127         private $mModuleMgr;
 128
 129         /**
 130          * @param ApiMain $main
 131          * @param string $action
 132          */
 133         public function __construct( ApiMain $main, $action ) {
 134                 parent::__construct( $main, $action );
 135
 136                 $this->mModuleMgr = new ApiModuleManager( $this );
 137
 138                 // Allow custom modules to be added in LocalSettings.php
 139                 $config = $this->getConfig();
 140                 $this->mModuleMgr->addModules( self::$QueryPropModules, 'prop' );
 141                 $this->mModuleMgr->addModules( $config->get( 'APIPropModules' ), 'prop' );
 142                 $this->mModuleMgr->addModules( self::$QueryListModules, 'list' );
 143                 $this->mModuleMgr->addModules( $config->get( 'APIListModules' ), 'list' );
 144                 $this->mModuleMgr->addModules( self::$QueryMetaModules, 'meta' );
 145                 $this->mModuleMgr->addModules( $config->get( 'APIMetaModules' ), 'meta' );
 146
 147                 Hooks::run( 'ApiQuery::moduleManager', array( $this->mModuleMgr ) );
 148
 149                 // Create PageSet that will process titles/pageids/revids/generator
 150                 $this->mPageSet = new ApiPageSet( $this );
 151         }
 152
 153         /**
 154          * Overrides to return this instance's module manager.
 155          * @return ApiModuleManager
 156          */
 157         public function getModuleManager() {
 158                 return $this->mModuleMgr;
 159         }
 160
 161         /**
 162          * Get the query database connection with the given name.
 163          * If no such connection has been requested before, it will be created.
 164          * Subsequent calls with the same $name will return the same connection
 165          * as the first, regardless of the values of $db and $groups
 166          * @param string $name Name to assign to the database connection
 167          * @param int $db One of the DB_* constants
 168          * @param array $groups Query groups
 169          * @return DatabaseBase
 170          */
 171         public function getNamedDB( $name, $db, $groups ) {
 172                 if ( !array_key_exists( $name, $this->mNamedDB ) ) {
 173                         $this->mNamedDB[$name] = wfGetDB( $db, $groups );
 174                 }
 175
 176                 return $this->mNamedDB[$name];
 177         }
 178
 179         /**
 180          * Gets the set of pages the user has requested (or generated)
 181          * @return ApiPageSet
 182          */
 183         public function getPageSet() {
 184                 return $this->mPageSet;
 185         }
 186
 187         /**
 188          * Get the generators array mapping module names to class names
 189          * @deprecated since 1.21, list of generators is maintained by ApiPageSet
 190          * @return array Array(modulename => classname)
 191          */
 192         public function getGenerators() {
 193                 wfDeprecated( __METHOD__, '1.21' );
 194                 $gens = array();
 195                 foreach ( $this->mModuleMgr->getNamesWithClasses() as $name => $class ) {
 196                         if ( is_subclass_of( $class, 'ApiQueryGeneratorBase' ) ) {
 197                                 $gens[$name] = $class;
 198                         }
 199                 }
 200
 201                 return $gens;
 202         }
 203
 204         /**
 205          * Get whether the specified module is a prop, list or a meta query module
 206          * @deprecated since 1.21, use getModuleManager()->getModuleGroup()
 207          * @param string $moduleName Name of the module to find type for
 208          * @return string|null
 209          */
 210         function getModuleType( $moduleName ) {
 211                 return $this->getModuleManager()->getModuleGroup( $moduleName );
 212         }
 213
 214         /**
 215          * @return ApiFormatRaw|null
 216          */
 217         public function getCustomPrinter() {
 218                 // If &exportnowrap is set, use the raw formatter
 219                 if ( $this->getParameter( 'export' ) &&
 220                         $this->getParameter( 'exportnowrap' )
 221                 ) {
 222                         return new ApiFormatRaw( $this->getMain(),
 223                                 $this->getMain()->createPrinterByName( 'xml' ) );
 224                 } else {
 225                         return null;
 226                 }
 227         }
 228
 229         /**
 230          * Query execution happens in the following steps:
 231          * #1 Create a PageSet object with any pages requested by the user
 232          * #2 If using a generator, execute it to get a new ApiPageSet object
 233          * #3 Instantiate all requested modules.
 234          *    This way the PageSet object will know what shared data is required,
 235          *    and minimize DB calls.
 236          * #4 Output all normalization and redirect resolution information
 237          * #5 Execute all requested modules
 238          */
 239         public function execute() {
 240                 $this->mParams = $this->extractRequestParams();
 241
 242                 // Instantiate requested modules
 243                 $allModules = array();
 244                 $this->instantiateModules( $allModules, 'prop' );
 245                 $propModules = array_keys( $allModules );
 246                 $this->instantiateModules( $allModules, 'list' );
 247                 $this->instantiateModules( $allModules, 'meta' );
 248
 249                 // Filter modules based on continue parameter
 250                 $continuationManager = new ApiContinuationManager( $this, $allModules, $propModules );
 251                 $this->setContinuationManager( $continuationManager );
 252                 $modules = $continuationManager->getRunModules();
 253
 254                 if ( !$continuationManager->isGeneratorDone() ) {
 255                         // Query modules may optimize data requests through the $this->getPageSet()
 256                         // object by adding extra fields from the page table.
 257                         foreach ( $modules as $module ) {
 258                                 $module->requestExtraData( $this->mPageSet );
 259                         }
 260                         // Populate page/revision information
 261                         $this->mPageSet->execute();
 262                         // Record page information (title, namespace, if exists, etc)
 263                         $this->outputGeneralPageInfo();
 264                 } else {
 265                         $this->mPageSet->executeDryRun();
 266                 }
 267
 268                 $cacheMode = $this->mPageSet->getCacheMode();
 269
 270                 // Execute all unfinished modules
 271                 /** @var $module ApiQueryBase */
 272                 foreach ( $modules as $module ) {
 273                         $params = $module->extractRequestParams();
 274                         $cacheMode = $this->mergeCacheMode(
 275                                 $cacheMode, $module->getCacheMode( $params ) );
 276                         $module->execute();
 277                         Hooks::run( 'APIQueryAfterExecute', array( &$module ) );
 278                 }
 279
 280                 // Set the cache mode
 281                 $this->getMain()->setCacheMode( $cacheMode );
 282
 283                 // Write the continuation data into the result
 284                 $this->setContinuationManager( null );
 285                 if ( $this->mParams['rawcontinue'] ) {
 286                         $data = $continuationManager->getRawContinuation();
 287                         if ( $data ) {
 288                                 $this->getResult()->addValue( null, 'query-continue', $data,
 289                                         ApiResult::ADD_ON_TOP | ApiResult::NO_SIZE_CHECK );
 290                         }
 291                 } else {
 292                         $continuationManager->setContinuationIntoResult( $this->getResult() );
 293                 }
 294         }
 295
 296         /**
 297          * Update a cache mode string, applying the cache mode of a new module to it.
 298          * The cache mode may increase in the level of privacy, but public modules
 299          * added to private data do not decrease the level of privacy.
 300          *
 301          * @param string $cacheMode
 302          * @param string $modCacheMode
 303          * @return string
 304          */
 305         protected function mergeCacheMode( $cacheMode, $modCacheMode ) {
 306                 if ( $modCacheMode === 'anon-public-user-private' ) {
 307                         if ( $cacheMode !== 'private' ) {
 308                                 $cacheMode = 'anon-public-user-private';
 309                         }
 310                 } elseif ( $modCacheMode === 'public' ) {
 311                         // do nothing, if it's public already it will stay public
 312                 } else { // private
 313                         $cacheMode = 'private';
 314                 }
 315
 316                 return $cacheMode;
 317         }
 318
 319         /**
 320          * Create instances of all modules requested by the client
 321          * @param array $modules To append instantiated modules to
 322          * @param string $param Parameter name to read modules from
 323          */
 324         private function instantiateModules( &$modules, $param ) {
 325                 $wasPosted = $this->getRequest()->wasPosted();
 326                 if ( isset( $this->mParams[$param] ) ) {
 327                         foreach ( $this->mParams[$param] as $moduleName ) {
 328                                 $instance = $this->mModuleMgr->getModule( $moduleName, $param );
 329                                 if ( $instance === null ) {
 330                                         ApiBase::dieDebug( __METHOD__, 'Error instantiating module' );
 331                                 }
 332                                 if ( !$wasPosted && $instance->mustBePosted() ) {
 333                                         $this->dieUsageMsgOrDebug( array( 'mustbeposted', $moduleName ) );
 334                                 }
 335                                 // Ignore duplicates. TODO 2.0: die()?
 336                                 if ( !array_key_exists( $moduleName, $modules ) ) {
 337                                         $modules[$moduleName] = $instance;
 338                                 }
 339                         }
 340                 }
 341         }
 342
 343         /**
 344          * Appends an element for each page in the current pageSet with the
 345          * most general information (id, title), plus any title normalizations
 346          * and missing or invalid title/pageids/revids.
 347          */
 348         private function outputGeneralPageInfo() {
 349                 $pageSet = $this->getPageSet();
 350                 $result = $this->getResult();
 351
 352                 // We can't really handle max-result-size failure here, but we need to
 353                 // check anyway in case someone set the limit stupidly low.
 354                 $fit = true;
 355
 356                 $values = $pageSet->getNormalizedTitlesAsResult( $result );
 357                 if ( $values ) {
 358                         $fit = $fit && $result->addValue( 'query', 'normalized', $values );
 359                 }
 360                 $values = $pageSet->getConvertedTitlesAsResult( $result );
 361                 if ( $values ) {
 362                         $fit = $fit && $result->addValue( 'query', 'converted', $values );
 363                 }
 364                 $values = $pageSet->getInterwikiTitlesAsResult( $result, $this->mParams['iwurl'] );
 365                 if ( $values ) {
 366                         $fit = $fit && $result->addValue( 'query', 'interwiki', $values );
 367                 }
 368                 $values = $pageSet->getRedirectTitlesAsResult( $result );
 369                 if ( $values ) {
 370                         $fit = $fit && $result->addValue( 'query', 'redirects', $values );
 371                 }
 372                 $values = $pageSet->getMissingRevisionIDsAsResult( $result );
 373                 if ( $values ) {
 374                         $fit = $fit && $result->addValue( 'query', 'badrevids', $values );
 375                 }
 376
 377                 // Page elements
 378                 $pages = array();
 379
 380                 // Report any missing titles
 381                 foreach ( $pageSet->getMissingTitles() as $fakeId => $title ) {
 382                         $vals = array();
 383                         ApiQueryBase::addTitleInfo( $vals, $title );
 384                         $vals['missing'] = true;
 385                         $pages[$fakeId] = $vals;
 386                 }
 387                 // Report any invalid titles
 388                 foreach ( $pageSet->getInvalidTitlesAndReasons() as $fakeId => $data ) {
 389                         $pages[$fakeId] = $data + array( 'invalid' => true );
 390                 }
 391                 // Report any missing page ids
 392                 foreach ( $pageSet->getMissingPageIDs() as $pageid ) {
 393                         $pages[$pageid] = array(
 394                                 'pageid' => $pageid,
 395                                 'missing' => true
 396                         );
 397                 }
 398                 // Report special pages
 399                 /** @var $title Title */
 400                 foreach ( $pageSet->getSpecialTitles() as $fakeId => $title ) {
 401                         $vals = array();
 402                         ApiQueryBase::addTitleInfo( $vals, $title );
 403                         $vals['special'] = true;
 404                         if ( $title->isSpecialPage() &&
 405                                 !SpecialPageFactory::exists( $title->getDBkey() )
 406                         ) {
 407                                 $vals['missing'] = true;
 408                         } elseif ( $title->getNamespace() == NS_MEDIA &&
 409                                 !wfFindFile( $title )
 410                         ) {
 411                                 $vals['missing'] = true;
 412                         }
 413                         $pages[$fakeId] = $vals;
 414                 }
 415
 416                 // Output general page information for found titles
 417                 foreach ( $pageSet->getGoodTitles() as $pageid => $title ) {
 418                         $vals = array();
 419                         $vals['pageid'] = $pageid;
 420                         ApiQueryBase::addTitleInfo( $vals, $title );
 421                         $pages[$pageid] = $vals;
 422                 }
 423
 424                 if ( count( $pages ) ) {
 425                         $pageSet->populateGeneratorData( $pages );
 426                         ApiResult::setArrayType( $pages, 'BCarray' );
 427
 428                         if ( $this->mParams['indexpageids'] ) {
 429                                 $pageIDs = array_keys( ApiResult::stripMetadataNonRecursive( $pages ) );
 430                                 // json treats all map keys as strings - converting to match
 431                                 $pageIDs = array_map( 'strval', $pageIDs );
 432                                 ApiResult::setIndexedTagName( $pageIDs, 'id' );
 433                                 $fit = $fit && $result->addValue( 'query', 'pageids', $pageIDs );
 434                         }
 435
 436                         ApiResult::setIndexedTagName( $pages, 'page' );
 437                         $fit = $fit && $result->addValue( 'query', 'pages', $pages );
 438                 }
 439
 440                 if ( !$fit ) {
 441                         $this->dieUsage(
 442                                 'The value of $wgAPIMaxResultSize on this wiki is ' .
 443                                         'too small to hold basic result information',
 444                                 'badconfig'
 445                         );
 446                 }
 447
 448                 if ( $this->mParams['export'] ) {
 449                         $this->doExport( $pageSet, $result );
 450                 }
 451         }
 452
 453         /**
 454          * This method is called by the generator base when generator in the smart-continue
 455          * mode tries to set 'query-continue' value. ApiQuery stores those values separately
 456          * until the post-processing when it is known if the generation should continue or repeat.
 457          * @deprecated since 1.24
 458          * @param ApiQueryGeneratorBase $module Generator module
 459          * @param string $paramName
 460          * @param mixed $paramValue
 461          * @return bool True if processed, false if this is a legacy continue
 462          */
 463         public function setGeneratorContinue( $module, $paramName, $paramValue ) {
 464                 wfDeprecated( __METHOD__, '1.24' );
 465                 $this->getContinuationManager()->addGeneratorContinueParam( $module, $paramName, $paramValue );
 466                 return !$this->getParameter( 'rawcontinue' );
 467         }
 468
 469         /**
 470          * @param ApiPageSet $pageSet Pages to be exported
 471          * @param ApiResult $result Result to output to
 472          */
 473         private function doExport( $pageSet, $result ) {
 474                 $exportTitles = array();
 475                 $titles = $pageSet->getGoodTitles();
 476                 if ( count( $titles ) ) {
 477                         $user = $this->getUser();
 478                         /** @var $title Title */
 479                         foreach ( $titles as $title ) {
 480                                 if ( $title->userCan( 'read', $user ) ) {
 481                                         $exportTitles[] = $title;
 482                                 }
 483                         }
 484                 }
 485
 486                 $exporter = new WikiExporter( $this->getDB() );
 487                 // WikiExporter writes to stdout, so catch its
 488                 // output with an ob
 489                 ob_start();
 490                 $exporter->openStream();
 491                 foreach ( $exportTitles as $title ) {
 492                         $exporter->pageByTitle( $title );
 493                 }
 494                 $exporter->closeStream();
 495                 $exportxml = ob_get_contents();
 496                 ob_end_clean();
 497
 498                 // Don't check the size of exported stuff
 499                 // It's not continuable, so it would cause more
 500                 // problems than it'd solve
 501                 if ( $this->mParams['exportnowrap'] ) {
 502                         $result->reset();
 503                         // Raw formatter will handle this
 504                         $result->addValue( null, 'text', $exportxml, ApiResult::NO_SIZE_CHECK );
 505                         $result->addValue( null, 'mime', 'text/xml', ApiResult::NO_SIZE_CHECK );
 506                 } else {
 507                         $result->addValue( 'query', 'export', $exportxml, ApiResult::NO_SIZE_CHECK );
 508                         $result->addValue( 'query', ApiResult::META_BC_SUBELEMENTS, array( 'export' ) );
 509                 }
 510         }
 511
 512         public function getAllowedParams( $flags = 0 ) {
 513                 $result = array(
 514                         'prop' => array(
 515                                 ApiBase::PARAM_ISMULTI => true,
 516                                 ApiBase::PARAM_TYPE => 'submodule',
 517                         ),
 518                         'list' => array(
 519                                 ApiBase::PARAM_ISMULTI => true,
 520                                 ApiBase::PARAM_TYPE => 'submodule',
 521                         ),
 522                         'meta' => array(
 523                                 ApiBase::PARAM_ISMULTI => true,
 524                                 ApiBase::PARAM_TYPE => 'submodule',
 525                         ),
 526                         'indexpageids' => false,
 527                         'export' => false,
 528                         'exportnowrap' => false,
 529                         'iwurl' => false,
 530                         'continue' => array(
 531                                 ApiBase::PARAM_HELP_MSG => 'api-help-param-continue',
 532                         ),
 533                         'rawcontinue' => false,
 534                 );
 535                 if ( $flags ) {
 536                         $result += $this->getPageSet()->getFinalParams( $flags );
 537                 }
 538
 539                 return $result;
 540         }
 541
 542         /**
 543          * Override the parent to generate help messages for all available query modules.
 544          * @deprecated since 1.25
 545          * @return string
 546          */
 547         public function makeHelpMsg() {
 548                 wfDeprecated( __METHOD__, '1.25' );
 549
 550                 // Use parent to make default message for the query module
 551                 $msg = parent::makeHelpMsg();
 552
 553                 $querySeparator = str_repeat( '--- ', 12 );
 554                 $moduleSeparator = str_repeat( '*** ', 14 );
 555                 $msg .= "\n$querySeparator Query: Prop  $querySeparator\n\n";
 556                 $msg .= $this->makeHelpMsgHelper( 'prop' );
 557                 $msg .= "\n$querySeparator Query: List  $querySeparator\n\n";
 558                 $msg .= $this->makeHelpMsgHelper( 'list' );
 559                 $msg .= "\n$querySeparator Query: Meta  $querySeparator\n\n";
 560                 $msg .= $this->makeHelpMsgHelper( 'meta' );
 561                 $msg .= "\n\n$moduleSeparator Modules: continuation  $moduleSeparator\n\n";
 562
 563                 return $msg;
 564         }
 565
 566         /**
 567          * For all modules of a given group, generate help messages and join them together
 568          * @deprecated since 1.25
 569          * @param string $group Module group
 570          * @return string
 571          */
 572         private function makeHelpMsgHelper( $group ) {
 573                 $moduleDescriptions = array();
 574
 575                 $moduleNames = $this->mModuleMgr->getNames( $group );
 576                 sort( $moduleNames );
 577                 foreach ( $moduleNames as $name ) {
 578                         /**
 579                          * @var $module ApiQueryBase
 580                          */
 581                         $module = $this->mModuleMgr->getModule( $name );
 582
 583                         $msg = ApiMain::makeHelpMsgHeader( $module, $group );
 584                         $msg2 = $module->makeHelpMsg();
 585                         if ( $msg2 !== false ) {
 586                                 $msg .= $msg2;
 587                         }
 588                         if ( $module instanceof ApiQueryGeneratorBase ) {
 589                                 $msg .= "Generator:\n  This module may be used as a generator\n";
 590                         }
 591                         $moduleDescriptions[] = $msg;
 592                 }
 593
 594                 return implode( "\n", $moduleDescriptions );
 595         }
 596
 597         protected function getExamplesMessages() {
 598                 return array(
 599                         'action=query&prop=revisions&meta=siteinfo&' .
 600                                 'titles=Main%20Page&rvprop=user|comment&continue='
 601                                 => 'apihelp-query-example-revisions',
 602                         'action=query&generator=allpages&gapprefix=API/&prop=revisions&continue='
 603                                 => 'apihelp-query-example-allpages',
 604                 );
 605         }
 606
 607         public function getHelpUrls() {
 608                 return array(
 609                         'https://www.mediawiki.org/wiki/API:Query',
 610                         'https://www.mediawiki.org/wiki/API:Meta',
 611                         'https://www.mediawiki.org/wiki/API:Properties',
 612                         'https://www.mediawiki.org/wiki/API:Lists',
 613                 );
 614         }
 615 }